Estuaries are diverse systems characterized by a bidirectional exchange flow, with a near-bottom landward inflow of saline seawater, which is mixed with riverine freshwater and transformed into a near-surface outflow. Aside from the density gradient between the river and the ocean, wind is a key mechanism in estuaries. The present study shows results describing the influence of wind on the estuarine exchange flow. A newly derived analytical formulation of wind-driven along-estuary velocity profiles motivates a critical basic Wedderburn as a measure for the sensitivity of an estuary to wind.